Daylight Saving Time: Why Some Have a Hard Time Making the Switch

For the most part, adjusting our clocks an hour ahead—as we will do this weekend—comes as good news: it is a welcome change from the long, dark winter.

Even though a one-hour time change does not sound like something that could do much harm, it can have some alarming effects on the body’s internal clock, which scientists call the circadian rhythm, said Theresa Lee, dean of the College of Arts and Sciences and a professor of psychology.

The “spring forward” time change is often more difficult than the “fall back” change because it means an hour less of sleep.

Even if you are well rested, an hour time change could leave you feeling sleep deprived, said Lee, who conducts research on sleep patterns over the life cycle and how sleep patterns and the need for sleep vary by age.

If you are already sleep deprived, one fewer hour can leave you feeling worse.

The good news is that it takes only about one day to adjust for each hour of time change.